Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/08—Copolymers of styrene
  • C08L25/12—Copolymers of styrene with unsaturated nitriles
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L55/00—Compositions of homopolymers or copolymers, obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in groups C08L23/00 - C08L53/00
  • C08L55/02—ABS [Acrylonitrile-Butadiene-Styrene] polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L69/00—Compositions of polycarbonates; Compositions of derivatives of polycarbonates

Definitions

• Blends of styrene/acrylonitrile polymers with polycarbonates based on tetra-alkylated diphenols are known. (See, for example, DE-OS (German Published Application) No. 2,329,585, DE-OS (German Published Specification) No. 2,329,646 and DE-OS (German Published Specification) No. 3,118,861). Although such blends containing styrene/acrylonitrile copolymers exhibit a certain degree of compatibility, they form separate phases at room temperature and also in the molten state when commercial styrene/acrylonitrile copolymers whose styrene/acrylonitrile ratio is not more than about 75% by weight:25% by weight are used.
• Blends of this type are prepared at temperatures of up to 260° C. (or up to 250° C.) [see DE-OS (German Published Specification) No. 2,329,646, page 20, and DE-OS (German Published Specification) No. 2,329,585, page 12].
• blends of tetramethylbisphenol A polycarbonates with polystyrenes exhibit completely different behaviour, since they form single-phase mixtures at temperatures up to about 240° C. in all weight ratios; however, these mixtures separate into two phases above this temperature (R. Casper and L. Morbitzer, Angew. Makrom. Chem. 58/59 (1977) 1-35).
• Blends of tetramethylbisphenol F-containing polycarbonates cannot in general be mixed with polystyrene to give a single phase.
• the choice of mixing temperature is therefore not associated with the above problems.
• the present invention therefore relates to a process for the preparation of polymer blends of
• thermoplastic aromatic tetramethylbisphenol F-containing polycarbonate A-1 to 99% by weight of a thermoplastic aromatic tetramethylbisphenol F-containing polycarbonate with
• a graft polymer consisting of 5 to 95% by weight of a styrene/acrylonitrile copolymer and 95 to 5% by weight of a butadiene rubber with 0 to 50% by weight of comonomers in addition to butadiene, of an ethylene/propylene/diene rubber or of a rubber consisting of acrylates with 0 to 30% by weight of other comonomers, prepared by polymerisation of styrene/acrylonitrile blends in the presence of one of the stated rubbers,
• the aromatic polycarbonate (A) contains at least 80% by weight of repeating structural units of the formulae 1 and, if appropriate, 2 ##STR1## and not more than 20% by weight of repeating structural units of the formula 3 ##STR2## wherein --O--R--O-- is another diphenolate radical, and the repeating structural units of the formula 1 must amount to at least 25% by weight of the aromatic polycarbonate, and that
• the amount of acrylonitrile in the styrene/acrylonitrile copolymer of components B and C is 1.5-15% by weight in each case, and that
• mixing is carried out at temperatures above 270° C., preferably from 270° to 340° C. and in particular from 280° to 330° C., in extruders or kneaders.
• the present invention furthermore relates to a process for the further processing of polymer blends consisting of the abovementioned components A and B and/or C to give shaped articles, which is characterised in that the polymer blends are moulded at temperatures above 270° C., preferably from 270° to 340° C. and in particular from 280° C. to 330° C., in extruders, injection moulding machines or high-temperature presses.
• a processing of such mixtures for example the injection moulding of test rods had been previously suggested more for lower temperatures up to a maximum of 260° C. (Compare DE-OS, German Published Application No. 2329585, pages 15 and 21).
• thermoplastic polycarbonates which can be used according to the invention as component A and are based on bis-(3,5-dimethyl-4-hydroxyphenyl)-methane have mean molecular weights Mw (weight average, determined by the light scattering method) from 10,000 to 200,000, preferably from 20,000 to 80,000 and in particular from 25,000 to 60,000.
• --O--R--O-- is a diphenolate radical with the exception of structures 1 and 2, which preferably has 6 to 30 C atoms.
• the polycarbonate components A used according to the invention can be branched in a conventional manner by incorporating branching agents.
• Suitable diphenols HO--R--OH (4) other than bis-(4-hydroxy-3,5-dimethylphenyl)-methane and 2,2-bis(4-hydroxy-3,5-dimethyl-phenyl)-propane are, for example, hydroquinone, resorcinol, dihydrodiphenyls, bis-(hydroxyphenyl)-alkanes, bis-hydroxyphenyl)-cycloalkanes, bis-(hydroxyphenyl)ethers, bis-(hydroxyphenyl) ketones and ⁇ , ⁇ '-bis-(hydroxyphenyl)-diisopropylbenzenes, and their derivatives which are alkylated in the nucleus and halogenated in the nucleus.
• Preferred other diphenols (4) are 2,2-bis-(4-hydroxyphenyl)-propane, bis-(4-hydroxyphenyl), 1,1-bis-(4-hydroxyphenyl)-cyclohexane, ⁇ , ⁇ '-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, 2,2-bis-(3-methyl-4-hydroxyphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dibromophenyl)-propane and 1,1,2,3,5-pentamethyl-3-(3,5-dimethyl-4-hydroxyphenyl)-indan-5-ol.
• the styrene/acrylonitrile copolymers which can be used according to the invention as component B are copolymers which can be prepared by copolymerisation of styrene and acrylonitrile and which contain 1.5 to 15% by weight of acrylonitrile as copolymerised units.
• the copolymerisation can be carried out by a free-radical method.
• Preferred styrene/acrylonitrile copolymers contain 6 to 13% by weight of acrylonitrile, particularly preferably 7 to 10% by weight of acrylonitrile.
• the molecular weights of these styrene/acrylonitrile copolymers can be varied within wide ranges.
• the molecular weights should be in the range from 30,000 to 600,000.
• the styrene/acrylonitrile copolymers can be prepared in principle by known processes, such as, for example, by mass, solution, suspension or emulsion polymerisation, and of course the process conditions which have to be maintained are those which are required for the copolymerisation of the monomers styrene and acrylonitrile to form styrene/acrylonitrile copolymers containing 1.5 to 15% by weight of acrylonitrile as copolymerised units.
• Preferred methods of preparation are emulsion, solution and mass copolymerisation.
• the copolymerisation can be carried out batchwise or continuously. The continuous reaction procedure is particularly advantageous.
• the styrene/acrylonitrile copolymers which can be used according to the invention generally possess a linear, non-crosslinked structure.
• the polymer blends according to the invention can also be prepared using styrene/acrylonitrile copolymers possessing a branched structure.
• the graft polymers which can be used according to the invention as component C are graft polymers consisting of 10 to 95% by weight of a styrene/acrylonitrile copolymer and 90 to 5% by weight of a rubber.
• the styrene/acrylonitrile copolymer contains 1.5 to 15% by weight of acrylonitrile, preferably 6 to 13% by weight of acrylonitrile and in particular 7 to 10% by weight of acrylonitrile, as copolymerised units.
• the graft polymer is preferably obtained by free radical copolymerisation of the graft monomers styrene and acrylonitrile in the presence of the rubber which constitutes the grafting base.
• the rubber which serves as the grafting base can be a butadiene rubber prepared from butadiene with up to 50% by weight of comonomers.
• Preferred rubbers of this type are butadiene/styrene and butadiene/acrylonitrile copolymers, and in particular polybutadiene.
• Other rubbers which can be employed as a grafting base are rubber-like acrylate copolymers and EPDM terpolymers.
• the graft polymerisation of the monomers styrene and acrylonitrile on to the rubber should be carried out by conventional methods, so that the resin component of the graft polymers has the desired styrene/acrylonitrile ratio within the range of the styrene/acrylonitrile ratios according to the invention.
• Preferred graft polymers contain 65 to 90% by weight of rubber and 35 to 10% by weight of styrene/acrylonitrile copolymer.
• Other preferred graft polymers contain 15 to 50% by weight of rubber and 85 to 50% by weight of styrene/acrylonitrile copolymer.
• the graft monomers can be polymerised in the presence of a latex of the grafting base in an emulsion with free radical initiators. If the grafting base is partially crosslinked and certain graft monomer/grafting base ratios are maintained, the particle size of the latex of the grafting base also determines the size of the graft rubber particles.
• the graft shell consists of chains of the polymer of the graft monomers, which chains are bonded chemically to the rubber particles. The grafting reaction is incomplete. In addition to the actual graft rubber particles, the ungrafted copolymer of the graft monomers is also formed.
• Graft polymers can also be prepared by mass solution polymerisation or mass suspension polymerisation if a monomer-soluble rubber is used as the the starting material. The size of the graft rubber particles is then fixed by the phase conversion, and can be varied both mechanically by stirring, and by chemically influencing the phase equilibrium (addition of dispersants). In general, particles>1 ⁇ m are obtained in this manner.
• graft polymers it is possible to use graft polymers to graft other particles which have a diameter from 0.05 to 10 ⁇ m, and a substantial part of the graft monomers can be included as a copolymer in the interior of the graft rubber particles. Particle diameters of from 0.05 to 1.2 ⁇ m or 0.05 to 0.6 ⁇ m are preferred. It is also possible for several graft polymers which differ from one another to be used simultaneously, it being possible for these graft polymers to differ in, for example, the degree of grafting, the grafting density and the size of the graft rubber particles.
• a mixture of a graft polymer with graft rubber particles having a d 50 value of from 0.35 to 10 ⁇ m and a graft polymer with graft rubber particles having a mean particle diameter d 50 of from 0.05 to 0.32 ⁇ m, that is to say a so-called bimodal system, is particularly suitable.
• the particle diameter d 50 is understood as meaning the mean diameter, above which and below which lie the diameters of 50% of the particles.
• the process, according to the invention, for the preparation and/or further processing of the polymer blends consisting of the components A and B, which form a single phase, or of the components A and C, or of the components A, B and C, which have a single-phase thermoplastic polymer matrix, permits rapid but nevertheless reliable preparation of polymer blends or of shaped articles having a good combination of properties, which was not to be expected at the relatively high process temperatures.
• customary additives reinforcing agents, mould-release agents, stabilisers and others can also be added to the polymer blends prepared according to the invention, before their preparation or before their further processing.
• the polymer blends or shaped articles prepared according to the invention are used in a conventional manner for applications in which constant contact with hot aqueous solutions or hot water is to be expected, for example for washing machines, hot-water boilers or tableware. They are also very suitable in the automobile sector, where advantageous fracture behaviour even under extreme conditions is required, for example for dashboards and interior panels. For interior panels, the good foamability and adhesion of polyurethane foams to the polymer blends of this invention are particularly advantageous.
• the blends are suitable for headlight reflectors.
• Polycarbonates A which are preferably used are those which contain at least 90% by weight of repeating bifunctional structural units of the formula 1 and, if appropriate, 2, and particularly preferred polycarbonates are those which contain only bifunctional structural units of the formulae 1 and, if appropriate, 2.
• the ratio of structural units of the formula 1 to those of the formula 2 in the polycarbonates which can be used according to the invention is between 25/75% by weight and 100/0% by weight. Ratios of above 50% by weight/50% by weight, particularly preferably of 100/0% by weight are preferred (structural units 1/structural units 2).
• the blends listed in the table were prepared by mixing the polycarbonates and the copolymers in the stated mixing ratio using a twin-screw extruder, at 290° C., via the melt. Test samples were produced from the resulting granules, at 300° C., by means of an injection moulding machine. The granules and the injection-moulded articles were subjected to differential thermal analysis. This showed that only one glass transition temperature T g is obtained in each case for the SAN-containing, transparent granules and test samples, and that the ABS-containing blends, which are opaque owing to the discrete rubber phase, exhibit only one T g in each case, in addition to the T g of the polybutadiene rubber (approx. -80° C.). This implies that the blends or the matrices of the blends constitute a single phase.
• ABS 35/10 Graft polymer of styrene and acrylonitrile in a weight ratio of 90:10 on polybutadiene rubber; proportion of polybutadiene equals 35% by weight of the graft polymer, particle size of the rubber is approx. 0.4 ⁇ m.

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• Compositions Of Macromolecular Compounds (AREA)

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Citations (7)

• 1983
  • 1983-12-07 DE DE19833344102 patent/DE3344102A1/de not_active Withdrawn
• 1984
  • 1984-11-26 US US06/674,846 patent/US4564654A/en not_active Expired - Fee Related
  • 1984-11-27 DE DE8484114312T patent/DE3464058D1/de not_active Expired
  • 1984-11-27 EP EP84114312A patent/EP0146021B1/de not_active Expired
  • 1984-12-03 JP JP59254258A patent/JPS60135444A/ja active Pending

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